Originally Posted by wintermute000
don't confuse the OP by talking about root and custom roms in the same breath
ROOTING IS NOT CUSTOM ROM
The same method to achieve both (unlock bootloader via htcdev) is the common factor
rooting by itself does NOTHING to improve anything on your phone, it gives you admin rights to then make further changes / mods (some of which can improve battery life sure)
but the biggie is custom ROM (like ARHD mentioned above) which is flashing an entire OS, thats where people talk about getting better batt life etc.
I suggest you go to XDA and get reading...
Both void your warranty
and as such I can't with all good conscience recommend anything requiring the use of htcdev to gain even root access.